A Nevada, Iowa, man who was previously arrested for harassing a transgender student allegedly sent an anthrax threat to a local elementary school, according to police.

Mondell Olson, 66, was charged with an aggravated misdemeanor after he allegedly sent a note with the word "anthras" on it to a teacher at Central Elementary School. Olson allegedly crushed up prescription medication and placed it in an envelope with the note.

The criminal complaint notes that Olson had previously been charged for allegedly harassing the same teacher on Feb. 15, 2017. At that time, Olson was charged with five counts of harassment and one aggravated misdemeanor after he allegedly called Nevada school officials and a household and said he would kill a transgender student.

He also allegedly sent an inappropriate message that was "sexual in nature" to a school district teacher at that time. The text message and voicemails did not appear to be connected, Nevada Police Chief Ricardo Martinez II said at that time.

Olson pleaded guilty to the February harassment-first degree and aggravated misdemeanor charges. He is currently in Story County Jail.